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For further information, see CMDT Part 32-02: Major Vaccine-Preventable Viral Infections

Key Features

Essentials of Diagnosis

  • Exposure 12–25 days before onset

  • Painful, swollen salivary glands, usually parotid

  • Frequent involvement of testes, pancreas, and meninges in unvaccinated individuals

  • Mumps can occur in appropriately vaccinated persons in highly vaccinated communities

General Considerations

  • Children are most commonly affected

  • Mumps is more serious in adults than in children

  • Appears to occur more commonly in males

  • However, in outbreaks, infection can affect patients in their second or third decades of life

  • Factors that contribute to outbreaks include

    • Efficacy of vaccines

    • Waning individual immunity

    • Crowded conditions

  • Incubation period: 12–25 days (average, 16–18 days)

  • Transmission

    • Direct contact with respiratory secretions or saliva or infected surfaces

    • Can also be airborne or via droplets

    • Subclinical infection, which is still transmissible, is present in up to one-third of affected individuals


  • Since the measles, mumps, and rubella (MMR) vaccine was introduced in 1989, the mumps case rate has decreased by more than 99%, with only a few hundred cases reported most years

  • From January 1 to January 25, 2020, preliminary data reported to the CDC showed 70 cases in 16 states

Clinical Findings

Symptoms and Signs

  • Parotid tenderness and overlying facial edema

    • Most common physical findings

    • Typically develop within 48 hours of the prodromal symptoms

    • Usually, one parotid gland enlarges before the other, but unilateral parotitis occurs in 25% of patients

    • The parotid duct (orifice of Stensen) may be red and swollen

    • Trismus may result from parotitis

  • High fever, testicular swelling, and tenderness (unilateral in 75% of cases)

    • Denote orchitis

    • Usually develops 7–10 days after the onset of parotitis

Differential Diagnosis

  • Calculi in the parotid ducts

  • Tumors

  • Cysts

  • Sarcoidosis

  • Cirrhosis

  • Diabetes

  • Bulimia

  • Pilocarpine usage

  • Sjögren syndrome

  • Parotitis may be produced by

    • Pyogenic organisms (eg, S aureus, gram-negative organisms [particularly in debilitated individuals with poor oral intake])

    • Drug reaction (phenothiazines, propylthiouracil)

    • Other viruses (HIV, influenza A, parainfluenza, EBV infection, coxsackieviruses, adenoviruses, HHV-6)

  • Inflammation of the lymph nodes


  • Characteristic clinical picture usually suffices for diagnosis

Laboratory Findings

  • Mild leukopenia with relative lymphocytosis may be present

  • Elevated serum amylase usually reflects salivary gland involvement rather than pancreatitis

  • Mild kidney injury is found in up to 60% of patients

  • An elevated serum IgM is considered diagnostic

    • Repeat testing 2–3 weeks after the onset of symptoms is recommended if the first assay is negative because the rise in IgM may be delayed, especially in vaccinated persons

  • A fourfold rise in complement-fixing antibodies to mumps virus in paired serum IgG also confirms infection

  • Anti-mumps IgM and IgG in the cerebrospinal fluid can confirm the diagnosis ...

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